Determination of the Interface States in Amorphous/Crystalline Silicon Using Surface Photovoltage Spectroscopy

The interface state level at amorphous/crystalline silicon (a-Si:H/c-Si) heterojunctions is identified with surface photovoltage spectroscopy (SPS). A positive slope alteration of SPS in 1.2 eV indicates there is a primarily empty state at Ev(c-Si)+0.75 eV. Using hydrogen plasma treatment (HPT) on c-Si surface, we observed a systematic variation in the SPS signal upon HPT time, which was associated to the change of interface state density. Our results show that the SPS can be used to optimize the heterojunction with intrinsic thin-layer solar cell preparation process.